.\" Copyright (c) 2007 by Michael Kerrisk <mtk.manpages@gmail.com>
.\"
.\" SPDX-License-Identifier: Linux-man-pages-copyleft
.\"
.TH sgetmask 2 2024-05-02 "Linux man-pages 6.9.1"
.SH NAME
sgetmask, ssetmask \- manipulation of signal mask (obsolete)
.SH LIBRARY
Standard C library
.RI ( libc ", " \-lc )
.SH SYNOPSIS
.nf
.BR "#include <sys/syscall.h>" "      /* Definition of " SYS_* " constants */"
.B #include <unistd.h>
.P
.B [[deprecated]] long syscall(SYS_sgetmask, void);
.BI "[[deprecated]] long syscall(SYS_ssetmask, long " newmask );
.fi
.SH DESCRIPTION
These system calls are obsolete.
.IR "Do not use them" ;
use
.BR sigprocmask (2)
instead.
.P
.BR sgetmask ()
returns the signal mask of the calling process.
.P
.BR ssetmask ()
sets the signal mask of the calling process to the value given in
.IR newmask .
The previous signal mask is returned.
.P
The signal masks dealt with by these two system calls
are plain bit masks (unlike the
.I sigset_t
used by
.BR sigprocmask (2));
use
.BR sigmask (3)
to create and inspect these masks.
.SH RETURN VALUE
.BR sgetmask ()
always successfully returns the signal mask.
.BR ssetmask ()
always succeeds, and returns the previous signal mask.
.SH ERRORS
These system calls always succeed.
.SH STANDARDS
Linux.
.SH HISTORY
Since Linux 3.16,
.\" f6187769dae48234f3877df3c4d99294cc2254fa
support for these system calls is optional,
depending on whether the kernel was built with the
.B CONFIG_SGETMASK_SYSCALL
option.
.SH NOTES
These system calls are unaware of signal numbers greater than 31
(i.e., real-time signals).
.P
These system calls do not exist on x86-64.
.P
It is not possible to block
.B SIGSTOP
or
.BR SIGKILL .
.SH SEE ALSO
.BR sigprocmask (2),
.BR signal (7)
